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* Fix breakage in shmem.cAl Viro2009-12-161-0/+2
| | | | | | | | | | Replacing error = 0; if (error) op with nothing is not quite an equivalent transformation ;-) Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* make generic_acl slightly more genericChristoph Hellwig2009-12-161-7/+10
| | | | | | | | | Now that we cache the ACL pointers in the generic inode all the generic_acl cruft can go away and generic_acl.c can directly implement xattr handlers dealing with the full Posix ACL semantics for in-memory filesystems. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* sanitize xattr handler prototypesChristoph Hellwig2009-12-161-9/+10
| | | | | | | | | | | | | | | | | | | | | Add a flags argument to struct xattr_handler and pass it to all xattr handler methods. This allows using the same methods for multiple handlers, e.g. for the ACL methods which perform exactly the same action for the access and default ACLs, just using a different underlying attribute. With a little more groundwork it'll also allow sharing the methods for the regular user/trusted/secure handlers in extN, ocfs2 and jffs2 like it's already done for xfs in this patch. Also change the inode argument to the handlers to a dentry to allow using the handlers mechnism for filesystems that require it later, e.g. cifs. [with GFS2 bits updated by Steven Whitehouse <swhiteho@redhat.com>] Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: James Morris <jmorris@namei.org> Acked-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Untangling ima mess, part 1: alloc_file()Al Viro2009-12-161-2/+0
| | | | | | | | | | There are 2 groups of alloc_file() callers: * ones that are followed by ima_counts_get * ones giving non-regular files So let's pull that ima_counts_get() into alloc_file(); it's a no-op in case of non-regular files. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* switch alloc_file() to passing struct pathAl Viro2009-12-161-6/+8
| | | | | | | ... and have the caller grab both mnt and dentry; kill leak in infiniband, while we are at it. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* switch shmem_file_setup() to alloc_file()Al Viro2009-12-161-12/+9
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* swap_info: note SWAP_MAP_SHMEMHugh Dickins2009-12-151-2/+9
| | | | | | | | | | | | | | | | While we're fiddling with the swap_map values, let's assign a particular value to shmem/tmpfs swap pages: their swap counts are never incremented, and it helps swapoff's try_to_unuse() a little if it can immediately distinguish those pages from process pages. Since we've no use for SWAP_MAP_BAD | COUNT_CONTINUED, we might as well use that 0xbf value for SWAP_MAP_SHMEM. Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* const: mark struct vm_struct_operationsAlexey Dobriyan2009-09-271-2/+2
| | | | | | | | | | | * mark struct vm_area_struct::vm_ops as const * mark vm_ops in AGP code But leave TTM code alone, something is fishy there with global vm_ops being used. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'writeback' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds2009-09-251-2/+3
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 'writeback' of git://git.kernel.dk/linux-2.6-block: writeback: writeback_inodes_sb() should use bdi_start_writeback() writeback: don't delay inodes redirtied by a fast dirtier writeback: make the super_block pinning more efficient writeback: don't resort for a single super_block in move_expired_inodes() writeback: move inodes from one super_block together writeback: get rid to incorrect references to pdflush in comments writeback: improve readability of the wb_writeback() continue/break logic writeback: cleanup writeback_single_inode() writeback: kupdate writeback shall not stop when more io is possible writeback: stop background writeback when below background threshold writeback: balance_dirty_pages() shall write more than dirtied pages fs: Fix busyloop in wb_writeback()
| * writeback: get rid to incorrect references to pdflush in commentsJens Axboe2009-09-251-2/+3
| | | | | | | | Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | Merge branch 'hwpoison' of ↵Linus Torvalds2009-09-241-2/+3
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6 * 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6: (21 commits) HWPOISON: Enable error_remove_page on btrfs HWPOISON: Add simple debugfs interface to inject hwpoison on arbitary PFNs HWPOISON: Add madvise() based injector for hardware poisoned pages v4 HWPOISON: Enable error_remove_page for NFS HWPOISON: Enable .remove_error_page for migration aware file systems HWPOISON: The high level memory error handler in the VM v7 HWPOISON: Add PR_MCE_KILL prctl to control early kill behaviour per process HWPOISON: shmem: call set_page_dirty() with locked page HWPOISON: Define a new error_remove_page address space op for async truncation HWPOISON: Add invalidate_inode_page HWPOISON: Refactor truncate to allow direct truncating of page v2 HWPOISON: check and isolate corrupted free pages v2 HWPOISON: Handle hardware poisoned pages in try_to_unmap HWPOISON: Use bitmask/action code for try_to_unmap behaviour HWPOISON: x86: Add VM_FAULT_HWPOISON handling to x86 page fault handler v2 HWPOISON: Add poison check to page fault handling HWPOISON: Add basic support for poisoned pages in fault handler v3 HWPOISON: Add new SIGBUS error codes for hardware poison signals HWPOISON: Add support for poison swap entries v2 HWPOISON: Export some rmap vma locking to outside world ...
| * HWPOISON: Enable .remove_error_page for migration aware file systemsAndi Kleen2009-09-161-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Enable removing of corrupted pages through truncation for a bunch of file systems: ext*, xfs, gfs2, ocfs2, ntfs These should cover most server needs. I chose the set of migration aware file systems for this for now, assuming they have been especially audited. But in general it should be safe for all file systems on the data area that support read/write and truncate. Caveat: the hardware error handler does not take i_mutex for now before calling the truncate function. Is that ok? Cc: tytso@mit.edu Cc: hch@infradead.org Cc: mfasheh@suse.com Cc: aia21@cantab.net Cc: hugh.dickins@tiscali.co.uk Cc: swhiteho@redhat.com Signed-off-by: Andi Kleen <ak@linux.intel.com>
| * HWPOISON: shmem: call set_page_dirty() with locked pageWu Fengguang2009-09-161-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The dirtying of page and set_page_dirty() can be moved into the page lock. - In shmem_write_end(), the page was dirtied while the page lock was held, but it's being marked dirty just after dropping the page lock. - In shmem_symlink(), both dirtying and marking can be moved into page lock. It's valuable for the hwpoison code to know whether one bad page can be dropped without losing data. It mainly judges by testing the PG_dirty bit after taking the page lock. So it becomes important that the dirtying of page and the marking of dirtiness are both done inside the page lock. Which is a common practice, but sadly not a rule. The noticeable exceptions are - mapped pages - pages with buffer_heads The above pages could go dirty at any time. Fortunately the hwpoison will unmap the page and release the buffer_heads beforehand anyway. Many other types of pages (eg. metadata pages) can also be dirtied at will by their owners, the hwpoison code cannot do meaningful things to them anyway. Only the dirtiness of pagecache pages owned by regular files are interested. v2: AK: Add comment about set_page_dirty rules (suggested by Peter Zijlstra) Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andi Kleen <ak@linux.intel.com>
* | shmem: initialize struct shmem_sb_info to zeroPekka Enberg2009-09-221-4/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fixes the following kmemcheck false positive (the compiler is using a 32-bit mov to load the 16-bit sbinfo->mode in shmem_fill_super): [ 0.337000] Total of 1 processors activated (3088.38 BogoMIPS). [ 0.352000] CPU0 attaching NULL sched-domain. [ 0.360000] WARNING: kmemcheck: Caught 32-bit read from uninitialized memory (9f8020fc) [ 0.361000] a44240820000000041f6998100000000000000000000000000000000ff030000 [ 0.368000] i i i i i i i i i i i i i i i i u u u u i i i i i i i i i i u u [ 0.375000] ^ [ 0.376000] [ 0.377000] Pid: 9, comm: khelper Not tainted (2.6.31-tip #206) P4DC6 [ 0.378000] EIP: 0060:[<810a3a95>] EFLAGS: 00010246 CPU: 0 [ 0.379000] EIP is at shmem_fill_super+0xb5/0x120 [ 0.380000] EAX: 00000000 EBX: 9f845400 ECX: 824042a4 EDX: 8199f641 [ 0.381000] ESI: 9f8020c0 EDI: 9f845400 EBP: 9f81af68 ESP: 81cd6eec [ 0.382000] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 [ 0.383000] CR0: 8005003b CR2: 9f806200 CR3: 01ccd000 CR4: 000006d0 [ 0.384000] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 [ 0.385000] DR6: ffff4ff0 DR7: 00000400 [ 0.386000] [<810c25fc>] get_sb_nodev+0x3c/0x80 [ 0.388000] [<810a3514>] shmem_get_sb+0x14/0x20 [ 0.390000] [<810c207f>] vfs_kern_mount+0x4f/0x120 [ 0.392000] [<81b2849e>] init_tmpfs+0x7e/0xb0 [ 0.394000] [<81b11597>] do_basic_setup+0x17/0x30 [ 0.396000] [<81b11907>] kernel_init+0x57/0xa0 [ 0.398000] [<810039b7>] kernel_thread_helper+0x7/0x10 [ 0.400000] [<ffffffff>] 0xffffffff [ 0.402000] khelper used greatest stack depth: 2820 bytes left [ 0.407000] calling init_mmap_min_addr+0x0/0x10 @ 1 [ 0.408000] initcall init_mmap_min_addr+0x0/0x10 returned 0 after 0 usecs Reported-by: Ingo Molnar <mingo@elte.hu> Analysed-by: Vegard Nossum <vegard.nossum@gmail.com> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi> Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | tmpfs: depend on shmemHugh Dickins2009-09-221-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | CONFIG_SHMEM off gives you (ramfs masquerading as) tmpfs, even when CONFIG_TMPFS is off: that's a little anomalous, and I'd intended to make more sense of it by removing CONFIG_TMPFS altogether, always enabling its code when CONFIG_SHMEM; but so many defconfigs have CONFIG_SHMEM on CONFIG_TMPFS off that we'd better leave that as is. But there is no point in asking for CONFIG_TMPFS if CONFIG_SHMEM is off: make TMPFS depend on SHMEM, which also prevents TMPFS_POSIX_ACL shmem_acl.o being pointlessly built into the kernel when SHMEM is off. And a selfish change, to prevent the world from being rebuilt when I switch between CONFIG_SHMEM on and off: the only CONFIG_SHMEM in the header files is mm.h shmem_lock() - give that a shmem.c stub instead. Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Acked-by: Matt Mackall <mpm@selenic.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: includecheck fix for mm/shmem.cJaswinder Singh Rajput2009-09-221-1/+0
| | | | | | | | | | | | | | | | | | | | | | Fix the following 'make includecheck' warning: mm/shmem.c: linux/vfs.h is included more than once. Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: add_to_swap_cache() does not return -EEXISTDaisuke Nishimura2009-09-221-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After commit 355cfa73 ("mm: modify swap_map and add SWAP_HAS_CACHE flag"), only the context which have set SWAP_HAS_CACHE flag by swapcache_prepare() or get_swap_page() would call add_to_swap_cache(). So add_to_swap_cache() doesn't return -EEXIST any more. Even though it doesn't return -EEXIST, it's not good behavior conceptually to call swapcache_prepare() in the -EEXIST case, because it means clearing SWAP_HAS_CACHE flag while the entry is on swap cache. This patch removes redundant codes and comments from callers of it, and adds VM_BUG_ON() in error path of add_to_swap_cache() and some comments. Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Driver Core: devtmpfs - kernel-maintained tmpfs-based /devKay Sievers2009-09-151-6/+3
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Devtmpfs lets the kernel create a tmpfs instance called devtmpfs very early at kernel initialization, before any driver-core device is registered. Every device with a major/minor will provide a device node in devtmpfs. Devtmpfs can be changed and altered by userspace at any time, and in any way needed - just like today's udev-mounted tmpfs. Unmodified udev versions will run just fine on top of it, and will recognize an already existing kernel-created device node and use it. The default node permissions are root:root 0600. Proper permissions and user/group ownership, meaningful symlinks, all other policy still needs to be applied by userspace. If a node is created by devtmps, devtmpfs will remove the device node when the device goes away. If the device node was created by userspace, or the devtmpfs created node was replaced by userspace, it will no longer be removed by devtmpfs. If it is requested to auto-mount it, it makes init=/bin/sh work without any further userspace support. /dev will be fully populated and dynamic, and always reflect the current device state of the kernel. With the commonly used dynamic device numbers, it solves the problem where static devices nodes may point to the wrong devices. It is intended to make the initial bootup logic simpler and more robust, by de-coupling the creation of the inital environment, to reliably run userspace processes, from a complex userspace bootstrap logic to provide a working /dev. Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Jan Blunck <jblunck@suse.de> Tested-By: Harald Hoyer <harald@redhat.com> Tested-By: Scott James Remnant <scott@ubuntu.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* shmfs: use 'check_acl' instead of 'permission'Linus Torvalds2009-09-081-3/+3
| | | | | | | | | | | shmfs wants purely standard POSIX ACL semantics, so we can use the new generic VFS layer POSIX ACL checking rather than cooking our own 'permission()' function. Reviewed-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Get "no acls for this inode" right, fix shmem breakageAl Viro2009-06-241-4/+1
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* switch shmem to inode->i_aclAl Viro2009-06-241-5/+4
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* mm cleanup: shmem_file_setup: 'char *' -> 'const char *' for name argumentSergei Trofimovich2009-06-161-1/+1
| | | | | | | | | | As function shmem_file_setup does not modify/allocate/free/pass given filename - mark it as const. Signed-off-by: Sergei Trofimovich <slyfox@inbox.ru> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: add swap cache interface for swap referenceKAMEZAWA Hiroyuki2009-06-161-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | In a following patch, the usage of swap cache is recorded into swap_map. This patch is for necessary interface changes to do that. 2 interfaces: - swapcache_prepare() - swapcache_free() are added for allocating/freeing refcnt from swap-cache to existing swap entries. But implementation itself is not changed under this patch. At adding swapcache_free(), memcg's hook code is moved under swapcache_free(). This is better than using scattered hooks. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Acked-by: Balbir Singh <balbir@in.ibm.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com> Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* integrity: move ima_counts_getMimi Zohar2009-05-221-1/+1
| | | | | | | | | | | | | | | | | Based on discussion on lkml (Andrew Morton and Eric Paris), move ima_counts_get down a layer into shmem/hugetlb__file_setup(). Resolves drm shmem_file_setup() usage case as well. HD comment: I still think you're doing this at the wrong level, but recognize that you probably won't be persuaded until a few more users of alloc_file() emerge, all wanting your ima_counts_get(). Resolving GEM's shmem_file_setup() is an improvement, so I'll say Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
* integrity: path_check updateMimi Zohar2009-05-221-1/+1
| | | | | | | | | | | - Add support in ima_path_check() for integrity checking without incrementing the counts. (Required for nfsd.) - rename and export opencount_get to ima_counts_get - replace ima_shm_check calls with ima_counts_get - export ima_path_check Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
* memcg: fix mem_cgroup_shrink_usage()Daisuke Nishimura2009-05-021-2/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Current mem_cgroup_shrink_usage() has two problems. 1. It doesn't call mem_cgroup_out_of_memory and doesn't update last_oom_jiffies, so pagefault_out_of_memory invokes global OOM. 2. Considering hierarchy, shrinking has to be done from the mem_over_limit, not from the memcg which the page would be charged to. mem_cgroup_try_charge_swapin() does all of these things properly, so we use it and call cancel_charge_swapin when it succeeded. The name of "shrink_usage" is not appropriate for this behavior, so we change it too. Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Li Zefan <lizf@cn.fujitsu.cn> Cc: Paul Menage <menage@google.com> Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* shmem: respect MAX_LFS_FILESIZEHugh Dickins2009-04-131-5/+20
| | | | | | | | | | | | | | | | | | | | | SHMEM_MAX_BYTES was derived from the maximum size of its triple-indirect swap vector, forgetting to take the MAX_LFS_FILESIZE limit into account. Never mind 256kB pages, even 8kB pages on 32-bit kernels allowed files to grow slightly bigger than that supposed maximum. Fix this by using the min of both (at build time not run time). And it happens that this calculation is good as far as 8MB pages on 32-bit or 16MB pages on 64-bit: though SHMSWP_MAX_INDEX gets truncated before that, it's truncated to such large numbers that we don't need to care. [akpm@linux-foundation.org: it needs pagemap.h] [akpm@linux-foundation.org: fix sparc64 min() warnings] Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: Yuri Tikhonov <yur@emcraft.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* shmem: fix division by zeroYuri Tikhonov2009-04-131-1/+1
| | | | | | | | | | | | | | | | | | | | | Fix a division by zero which we have in shmem_truncate_range() and shmem_unuse_inode() when using big PAGE_SIZE values (e.g. 256kB on ppc44x). With 256kB PAGE_SIZE, the ENTRIES_PER_PAGEPAGE constant becomes too large (0x1.0000.0000) on a 32-bit kernel, so this patch just changes its type from 'unsigned long' to 'unsigned long long'. Hugh: reverted its unsigned long longs in shmem_truncate_range() and shmem_getpage(): the pagecache index cannot be more than an unsigned long, so the divisions by zero occurred in unreached code. It's a pity we need any ULL arithmetic here, but I found no pretty way to avoid it. Signed-off-by: Yuri Tikhonov <yur@emcraft.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* shmem: writepage directly to swapHugh Dickins2009-04-011-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Synopsis: if shmem_writepage calls swap_writepage directly, most shmem swap loads benefit, and a catastrophic interaction between SLUB and some flash storage is avoided. shmem_writepage() has always been peculiar in making no attempt to write: it has just transferred a shmem page from file cache to swap cache, then let that page make its way around the LRU again before being written and freed. The idea was that people use tmpfs because they want those pages to stay in RAM; so although we give it an overflow to swap, we should resist writing too soon, giving those pages a second chance before they can be reclaimed. That was always questionable, and I've toyed with this patch for years; but never had a clear justification to depart from the original design. It became more questionable in 2.6.28, when the split LRU patches classed shmem and tmpfs pages as SwapBacked rather than as file_cache: that in itself gives them more resistance to reclaim than normal file pages. I prepared this patch for 2.6.29, but the merge window arrived before I'd completed gathering statistics to justify sending it in. Then while comparing SLQB against SLUB, running SLUB on a laptop I'd habitually used with SLAB, I found SLUB to run my tmpfs kbuild swapping tests five times slower than SLAB or SLQB - other machines slower too, but nowhere near so bad. Simpler "cp -a" swapping tests showed the same. slub_max_order=0 brings sanity to all, but heavy swapping is too far from normal to justify such a tuning. The crucial factor on that laptop turns out to be that I'm using an SD card for swap. What happens is this: By default, SLUB uses order-2 pages for shmem_inode_cache (and many other fs inodes), so creating tmpfs files under memory pressure brings lumpy reclaim into play. One subpage of the order is chosen from the bottom of the LRU as usual, then the other three picked out from their random positions on the LRUs. In a tmpfs load, many of these pages will be ones which already passed through shmem_writepage, so already have swap allocated. And though their offsets on swap were probably allocated sequentially, now that the pages are picked off at random, their swap offsets are scattered. But the flash storage on the SD card is very sensitive to having its writes merged: once swap is written at scattered offsets, performance falls apart. Rotating disk seeks increase too, but less disastrously. So: stop giving shmem/tmpfs pages a second pass around the LRU, write them out to swap as soon as their swap has been allocated. It's surely possible to devise an artificial load which runs faster the old way, one whose sizing is such that the tmpfs pages on their second pass are the ones that are wanted again, and other pages not. But I've not yet found such a load: on all machines, under the loads I've tried, immediate swap_writepage speeds up shmem swapping: especially when using the SLUB allocator (and more effectively than slub_max_order=0), but also with the others; and it also reduces the variance between runs. How much faster varies widely: a factor of five is rare, 5% is common. One load which might have suffered: imagine a swapping shmem load in a limited mem_cgroup on a machine with plenty of memory. Before 2.6.29 the swapcache was not charged, and such a load would have run quickest with the shmem swapcache never written to swap. But now swapcache is charged, so even this load benefits from shmem_writepage directly to swap. Apologies for the #ifndef CONFIG_SWAP swap_writepage() stub in swap.h: it's silly because that will never get called; but refactoring shmem.c sensibly according to CONFIG_SWAP will be a separate task. Signed-off-by: Hugh Dickins <hugh@veritas.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'master' into nextJames Morris2009-03-241-22/+21
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| * shmem: fix shared anonymous accountingHugh Dickins2009-02-251-22/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Each time I exit Firefox, /proc/meminfo's Committed_AS goes down almost 400 kB: OVERCOMMIT_NEVER would be allowing overcommits it should prohibit. Commit fc8744adc870a8d4366908221508bb113d8b72ee "Stop playing silly games with the VM_ACCOUNT flag" changed shmem_file_setup() to set the shmem file's VM_ACCOUNT flag according to VM_NORESERVE not being set in the vma flags; but did so only _after_ the shmem_acct_size(flags, size) call which is expected to pre-account a shared anonymous object. It's all clearer if we switch shmem.c over to use VM_NORESERVE throughout in place of !VM_ACCOUNT. But I very nearly sent in a patch which mistakenly removed the accounting from tmpfs files: shmem_get_inode()'s memset was good for not setting VM_ACCOUNT, but now it needs to set VM_NORESERVE. Rather than setting that by default, then perhaps clearing it again in shmem_file_setup(), let's pass it as a flag to shmem_get_inode(): that allows us to remove the #ifdef CONFIG_SHMEM from shmem_file_setup(). Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | integrity: shmem zero fixMimi Zohar2009-02-111-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Based on comments from Mike Frysinger and Randy Dunlap: (http://lkml.org/lkml/2009/2/9/262) - moved ima.h include before CONFIG_SHMEM test to fix compiler error on Blackfin: mm/shmem.c: In function 'shmem_zero_setup': mm/shmem.c:2670: error: implicit declaration of function 'ima_shm_check' - added 'struct linux_binprm' in ima.h to fix compiler warning on Blackfin: In file included from mm/shmem.c:32: include/linux/ima.h:25: warning: 'struct linux_binprm' declared inside parameter list include/linux/ima.h:25: warning: its scope is only this definition or declaration, which is probably not what you want - moved fs.h include within _LINUX_IMA_H definition Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: James Morris <jmorris@namei.org>
* | Merge branch 'master' into nextJames Morris2009-02-061-18/+86
|\ \ | |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: fs/namei.c Manually merged per: diff --cc fs/namei.c index 734f2b5,bbc15c2..0000000 --- a/fs/namei.c +++ b/fs/namei.c @@@ -860,9 -848,8 +849,10 @@@ static int __link_path_walk(const char nd->flags |= LOOKUP_CONTINUE; err = exec_permission_lite(inode); if (err == -EAGAIN) - err = vfs_permission(nd, MAY_EXEC); + err = inode_permission(nd->path.dentry->d_inode, + MAY_EXEC); + if (!err) + err = ima_path_check(&nd->path, MAY_EXEC); if (err) break; @@@ -1525,14 -1506,9 +1509,14 @@@ int may_open(struct path *path, int acc flag &= ~O_TRUNC; } - error = vfs_permission(nd, acc_mode); + error = inode_permission(inode, acc_mode); if (error) return error; + - error = ima_path_check(&nd->path, ++ error = ima_path_check(path, + acc_mode & (MAY_READ | MAY_WRITE | MAY_EXEC)); + if (error) + return error; /* * An append-only file must be opened in append mode for writing. */ Signed-off-by: James Morris <jmorris@namei.org>
| * Stop playing silly games with the VM_ACCOUNT flagLinus Torvalds2009-01-311-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The mmap_region() code would temporarily set the VM_ACCOUNT flag for anonymous shared mappings just to inform shmem_zero_setup() that it should enable accounting for the resulting shm object. It would then clear the flag after calling ->mmap (for the /dev/zero case) or doing shmem_zero_setup() (for the MAP_ANON case). This just resulted in vma merge issues, but also made for just unnecessary confusion. Use the already-existing VM_NORESERVE flag for this instead, and let shmem_{zero|file}_setup() just figure it out from that. This also happens to make it obvious that the new DRI2 GEM layer uses a non-reserving backing store for its object allocation - which is quite possibly not intentional. But since I didn't want to change semantics in this patch, I left it alone, and just updated the caller to use the new flag semantics. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * memcg: fix shmem's swap accountingKAMEZAWA Hiroyuki2009-01-081-18/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now, you can see following even when swap accounting is enabled. 1. Create Group 01, and 02. 2. allocate a "file" on tmpfs by a task under 01. 3. swap out the "file" (by memory pressure) 4. Read "file" from a task in group 02. 5. the charge of "file" is moved to group 02. This is not ideal behavior. This is because SwapCache which was loaded by read-ahead is not taken into account.. This is a patch to fix shmem's swapcache behavior. - remove mem_cgroup_cache_charge_swapin(). - Add SwapCache handler routine to mem_cgroup_cache_charge(). By this, shmem's file cache is charged at add_to_page_cache() with GFP_NOWAIT. - pass the page of swapcache to shrink_mem_cgroup. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * memcg: revert gfp mask fixKAMEZAWA Hiroyuki2009-01-081-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | My patch, memcg-fix-gfp_mask-of-callers-of-charge.patch changed gfp_mask of callers of charge to be GFP_HIGHUSER_MOVABLE for showing what will happen at memory reclaim. But in recent discussion, it's NACKed because it sounds ugly. This patch is for reverting it and add some clean up to gfp_mask of callers of charge. No behavior change but need review before generating HUNK in deep queue. This patch also adds explanation to meaning of gfp_mask passed to charge functions in memcontrol.h. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Hugh Dickins <hugh@veritas.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * memcg: handle swap cachesKAMEZAWA Hiroyuki2009-01-081-2/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | SwapCache support for memory resource controller (memcg) Before mem+swap controller, memcg itself should handle SwapCache in proper way. This is cut-out from it. In current memcg, SwapCache is just leaked and the user can create tons of SwapCache. This is a leak of account and should be handled. SwapCache accounting is done as following. charge (anon) - charged when it's mapped. (because of readahead, charge at add_to_swap_cache() is not sane) uncharge (anon) - uncharged when it's dropped from swapcache and fully unmapped. means it's not uncharged at unmap. Note: delete from swap cache at swap-in is done after rmap information is established. charge (shmem) - charged at swap-in. this prevents charge at add_to_page_cache(). uncharge (shmem) - uncharged when it's dropped from swapcache and not on shmem's radix-tree. at migration, check against 'old page' is modified to handle shmem. Comparing to the old version discussed (and caused troubles), we have advantages of - PCG_USED bit. - simple migrating handling. So, situation is much easier than several months ago, maybe. [hugh@veritas.com: memcg: handle swap caches build fix] Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Tested-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * memcg: fix gfp_mask of callers of chargeKAMEZAWA Hiroyuki2009-01-081-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix misuse of gfp_kernel. Now, most of callers of mem_cgroup_charge_xxx functions uses GFP_KERNEL. I think that this is from the fact that page_cgroup *was* dynamically allocated. But now, we allocate all page_cgroup at boot. And mem_cgroup_try_to_free_pages() reclaim memory from GFP_HIGHUSER_MOVABLE + specified GFP_RECLAIM_MASK. * This is because we just want to reduce memory usage. "Where we should reclaim from ?" is not a problem in memcg. This patch modifies gfp masks to be GFP_HIGUSER_MOVABLE if possible. Note: This patch is not for fixing behavior but for showing sane information in source code. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * shmem: unify regular and tiny shmemMatt Mackall2009-01-061-10/+71
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | tiny-shmem shares most of its 130 lines of code with shmem and tends to break when particular bits of shmem get modified. Unifying saves code and makes keeping these two in sync much easier. before: 14367 392 24 14783 39bf mm/shmem.o 396 72 8 476 1dc mm/tiny-shmem.o after: 14367 392 24 14783 39bf mm/shmem.o 412 72 8 492 1ec mm/shmem.o tiny Signed-off-by: Matt Mackall <mpm@selenic.com> Acked-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * mm: don't mark_page_accessed in shmem_faultHugh Dickins2009-01-061-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | Following "mm: don't mark_page_accessed in fault path", which now places a mark_page_accessed() in zap_pte_range(), we should remove the mark_page_accessed() from shmem_fault(). Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Johannes Weiner <hannes@saeurebad.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Integrity: IMA file free imbalanceMimi Zohar2009-02-061-0/+2
|/ | | | | | | | | | | | | | | | | | | | | The number of calls to ima_path_check()/ima_file_free() should be balanced. An extra call to fput(), indicates the file could have been accessed without first being measured. Although f_count is incremented/decremented in places other than fget/fput, like fget_light/fput_light and get_file, the current task must already hold a file refcnt. The call to __fput() is delayed until the refcnt becomes 0, resulting in ima_file_free() flagging any changes. - add hook to increment opencount for IPC shared memory(SYSV), shmat files, and /dev/zero - moved NULL iint test in opencount_get() Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
* CRED: Wrap task credential accesses in the core kernelDavid Howells2008-11-141-4/+4
| | | | | | | | | | | | | | | | | | | | Wrap access to task credentials so that they can be separated more easily from the task_struct during the introduction of COW creds. Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id(). Change some task->e?[ug]id to task_e?[ug]id(). In some places it makes more sense to use RCU directly rather than a convenient wrapper; these will be addressed by later patches. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-audit@redhat.com Cc: containers@lists.linux-foundation.org Cc: linux-mm@kvack.org Signed-off-by: James Morris <jmorris@namei.org>
* nfsd: fix vm overcommit crashAlan Cox2008-10-301-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | Junjiro R. Okajima reported a problem where knfsd crashes if you are using it to export shmemfs objects and run strict overcommit. In this situation the current->mm based modifier to the overcommit goes through a NULL pointer. We could simply check for NULL and skip the modifier but we've caught other real bugs in the past from mm being NULL here - cases where we did need a valid mm set up (eg the exec bug about a year ago). To preserve the checks and get the logic we want shuffle the checking around and add a new helper to the vm_ security wrappers Also fix a current->mm reference in nommu that should use the passed mm [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: fix build] Reported-by: Junjiro R. Okajima <hooanon05@yahoo.co.jp> Acked-by: James Morris <jmorris@namei.org> Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* SHM_LOCKED pages are unevictableLee Schermerhorn2008-10-201-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Shmem segments locked into memory via shmctl(SHM_LOCKED) should not be kept on the normal LRU, since scanning them is a waste of time and might throw off kswapd's balancing algorithms. Place them on the unevictable LRU list instead. Use the AS_UNEVICTABLE flag to mark address_space of SHM_LOCKed shared memory regions as unevictable. Then these pages will be culled off the normal LRU lists during vmscan. Add new wrapper function to clear the mapping's unevictable state when/if shared memory segment is munlocked. Add 'scan_mapping_unevictable_page()' to mm/vmscan.c to scan all pages in the shmem segment's mapping [struct address_space] for evictability now that they're no longer locked. If so, move them to the appropriate zone lru list. Changes depend on [CONFIG_]UNEVICTABLE_LRU. [kosaki.motohiro@jp.fujitsu.com: revert shm change] Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Kosaki Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* vmscan: split LRU lists into anon & file setsRik van Riel2008-10-201-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Split the LRU lists in two, one set for pages that are backed by real file systems ("file") and one for pages that are backed by memory and swap ("anon"). The latter includes tmpfs. The advantage of doing this is that the VM will not have to scan over lots of anonymous pages (which we generally do not want to swap out), just to find the page cache pages that it should evict. This patch has the infrastructure and a basic policy to balance how much we scan the anon lists and how much we scan the file lists. The big policy changes are in separate patches. [lee.schermerhorn@hp.com: collect lru meminfo statistics from correct offset] [kosaki.motohiro@jp.fujitsu.com: prevent incorrect oom under split_lru] [kosaki.motohiro@jp.fujitsu.com: fix pagevec_move_tail() doesn't treat unevictable page] [hugh@veritas.com: memcg swapbacked pages active] [hugh@veritas.com: splitlru: BDI_CAP_SWAP_BACKED] [akpm@linux-foundation.org: fix /proc/vmstat units] [nishimura@mxp.nes.nec.co.jp: memcg: fix handling of shmem migration] [kosaki.motohiro@jp.fujitsu.com: adjust Quicklists field of /proc/meminfo] [kosaki.motohiro@jp.fujitsu.com: fix style issue of get_scan_ratio()] Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* define page_file_cache() functionRik van Riel2008-10-201-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Define page_file_cache() function to answer the question: is page backed by a file? Originally part of Rik van Riel's split-lru patch. Extracted to make available for other, independent reclaim patches. Moved inline function to linux/mm_inline.h where it will be needed by subsequent "split LRU" and "noreclaim" patches. Unfortunately this needs to use a page flag, since the PG_swapbacked state needs to be preserved all the way to the point where the page is last removed from the LRU. Trying to derive the status from other info in the page resulted in wrong VM statistics in earlier split VM patchsets. The total number of page flags in use on a 32 bit machine after this patch is 19. [akpm@linux-foundation.org: fix up out-of-order merge fallout] [hugh@veritas.com: splitlru: shmem_getpage SetPageSwapBacked sooner[ Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: MinChan Kim <minchan.kim@gmail.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Export shmem_file_setup for DRM-GEMKeith Packard2008-10-181-0/+1
| | | | | | | | | | | GEM needs to create shmem files to back buffer objects. Though currently creation of files for objects could have been driven from userland, the modesetting work will require allocation of buffer objects before userland is running, for boot-time message display. Signed-off-by: Eric Anholt <eric@anholt.net> Cc: Nick Piggin <npiggin@suse.de> Signed-off-by: Dave Airlie <airlied@redhat.com>
* integrity: special fs magicMimi Zohar2008-10-131-3/+1
| | | | | | | | | | | | | | Discussion on the mailing list questioned the use of these magic values in userspace, concluding these values are already exported to userspace via statfs and their correct/incorrect usage is left up to the userspace application. - Move special fs magic number definitions to magic.h - Add magic.h include Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Reviewed-by: James Morris <jmorris@namei.org> Signed-off-by: James Morris <jmorris@namei.org>
* mm: rename page trylockNick Piggin2008-08-041-2/+2
| | | | | | | | | | | | | | | Converting page lock to new locking bitops requires a change of page flag operation naming, so we might as well convert it to something nicer (!TestSetPageLocked_Lock => trylock_page, SetPageLocked => set_page_locked). This also facilitates lockdeping of page lock. Signed-off-by: Nick Piggin <npiggin@suse.de> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tmpfs: fix kernel BUG in shmem_delete_inodeHugh Dickins2008-07-281-1/+2
| | | | | | | | | | | | | | | | | | | SuSE's insserve initscript ordering program hits kernel BUG at mm/shmem.c:814 on 2.6.26. It's using posix_fadvise on directories, and the shmem_readpage method added in 2.6.23 is letting POSIX_FADV_WILLNEED allocate useless pages to a tmpfs directory, incrementing i_blocks count but never decrementing it. Fix this by assigning shmem_aops (pointing to readpage and writepage and set_page_dirty) only when it's needed, on a regular file or a long symlink. Many thanks to Kel for outstanding bugreport and steps to reproduce it. Reported-by: Kel Modderman <kel@otaku42.de> Tested-by: Kel Modderman <kel@otaku42.de> Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: <stable@kernel.org> [2.6.25.x, 2.6.26.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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